Effect of microstructural degradation on the overtemperature rupture performance in Ru-containing Ni-based single crystal superalloys

Abstract

This work investigates the effect of microstructural degradation on the overtemperature rupture performance in Ru-containing Ni-based single crystal superalloys. Unlike the initial samples, the rupture lives in the degraded sample are largely lost, and adding Ru in the degraded sample increases the rupture life at 1120 °C/100 MPa and 1180 °C/100 MPa. Based on the difference in the microstructure and microstructural evolution in the initial and degraded samples. Their influence on the rupture performance can be derived. The enlarged width of the γ matrix is the major reason for the reduction of the rupture life and increase in the strain for the degraded sample compared to the initial samples. The existence of the dislocation network and the inhibition of the precipitation of the TCP phase are the major reasons for the lower rupture life reduction in the 5Ru degraded sample than in the 3Ru degraded sample. The mobility of the dislocation increases with the temperature, weakening the benefit effect caused by Ru.

Keywords

• Ni-based superalloys
• Microstructure degradation
• Ru element
• Overtemperature rupture performance